W639 woes

technodiv

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Hello all, it’s been a while since I was last on here but the time has come for me to ask for some owner experience advice!

I run a 2013 viano 3.0v6 it is the om642 engine. I recently took it in to my go to garage for the following problem:

On occasion the cab starts to smell of exhaust fumes. This can happen randomly as there isn’t a specific mileage/temperature point where it will occur.

I have noticed other potential problems, I call them potential because I don’t know if I’m being paranoid or if now looking for problems! I’m mentioning these as they may be related to the smell issue. These include:

Irregular gear change from the auto box (5g-tronic I think). The rev range regularly increases to around 2200 revs before it changes gear, this is from start off at lights or a junction up to 30mph. Revs will also very rarely and suddenly drop to around 1000rpm when travelling at about 10mph, the accelerator feels like it’s doing nothing and then all of a sudden the revs pick up and the van pulls like train?!

Im also hearing the tell tale signs of a blowing exhaust. When setting off and normal driving, I’m looking for an XR3i or Renault 5 GT T at the side of me with fluffy dice and go faster stripes ….. to only realise it’s me making all the commotion!

Could a blowing exhaust be making the cab smell of fumes or interfering with the gear change (I’m thinking back pressure for gear change)? The garage, who are no Mickey Mouse outfit, took the van before Christmas and couldn’t find anything wrong? It’s like the gaffa there said though …. ‘An owner becomes accustomed to the sound and feel of their vehicle and will notice changes’. I just feel a bit of tit when taking the van to them with non existent problems when they look a it. As stated earlier the problem with the smell is random (exhaust sound and gear change occurred after I took it to them last time).

If anyone has had similar experiences with these problems, I would be very grateful if you could give me some pointers.

Thank you in advance.
 
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technodiv

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It’s probably worth mentioning that the injector seal/s were done about 1500 miles ago and the transmission fluid was also done about 2000 miles ago. I noticed ‘oil’ dripping from the box when I removed the under tray a while back and to my horror, my ‘go to’ diagnosed a rear oil seal failure and further inspection found a seal on either end of a pipe (oil cooler pipe I think) had failed. All of which has since been sorted. I nearly fainted when I got the invoice 🤣
 

Larkone

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You need to get in an a STAR machine to read the live data as to why you are having issues with power - common problem is a failing turbo actuator.
 
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technodiv

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You need to get in an a STAR machine to read the live data as to why you are having issues with power - common problem is a failing turbo actuator.

Thank you for the reply, I’ll look into this 👍
 

MrGreedy

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Could the exhaust smell be a dpf regen?
You would notice this in slow or stationary traffic, as ideally DPF regens should take place above 50mph.
The reason I say this is some manufacturer vehicle manuals (e.g. VAG) state that when you get the DPF warning light, that you should go for a 30 minute drive and keep above 50mph.

You could check this by monitoring exhaust temperature using a Bluetooth OBD2 adapter and Torque on your phone. It would involve setting it up on your phone before each journey for a few hundred miles.
 
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technodiv

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Could the exhaust smell be a dpf regen?
You would notice this in slow or stationary traffic, as ideally DPF regens should take place above 50mph.
The reason I say this is some manufacturer vehicle manuals (e.g. VAG) state that when you get the DPF warning light, that you should go for a 30 minute drive and keep above 50mph.

You could check this by monitoring exhaust temperature using a Bluetooth OBD2 adapter and Torque on your phone. It would involve setting it up on your phone before each journey for a few hundred miles.

I suppose with the smell being random, It’s maybe something to look into?! I have an obd2 reader, granted that it is a bit Mickey Mouse. Bit there is all sorts of stuff on it 🤔 one of the ‘stuffs’ is live feed (if that’s the correct terminology) and I’m certain exhaust temp is on there, uncertain about torque though, what do you mean by this? Surely though when Mr (or Mrs) Merc designed the dpf they made sure that the cab didn’t fill with noxious gases (not trying to be a clever ****, just arguing with myself!)

Around 2000 miles ago the van was in limp mode and my go to confirmed dpf blockage/drama. A regen was forced and touch wood, all has been fine since. At this time I did try to work out when the dpf regen kicks in via the interweb and monitoring the OBD on a run but time forced me to just take it to the professionals 🤷‍♂️ Do you know when the regen kicks in? Is it by engine temp or timer? Apologies for all the ?? But I do love a good puzzle, less so when it affects the pocket!
 

MrGreedy

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Torque is an app you can download and one of the live data you can view is exhaust temp. If you already have something to do this, you don't need the Torque app.

The fumes might not be there by design if it's related to DPF regen, but it might be due to the engine getting really hot in the area of the DPF, and thereby stuff eternal to the engine giving off fumes. Spilt grease, leaking oil, deteriorating wiring insulation or other plastic gubbins in that vicinity. Hence many manufacturers advise above 50mph for cooling of the engine bay.

The DPF regen triggers on fill (Well, strictly pressure, and a full filter results in higher DPF pressure). When all working as intended, I would expect 400-800 miles between regens, depending on driving and engine health and therefore soot production. The regen will only start if certain other parameters are met e.g. more than 25% fuel in tank, a minimum speed and min exhaust temp.

If you interrupt a regen (by switching the engine off mid way through, and you wouldn't normally know because there is no dash indicator), then it will probably try to do another regen ASAP once the car is on again and the parameters are met.
 
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technodiv

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Torque is an app you can download and one of the live data you can view is exhaust temp. If you already have something to do this, you don't need the Torque app.

The fumes might not be there by design if it's related to DPF regen, but it might be due to the engine getting really hot in the area of the DPF, and thereby stuff eternal to the engine giving off fumes. Spilt grease, leaking oil, deteriorating wiring insulation or other plastic gubbins in that vicinity. Hence many manufacturers advise above 50mph for cooling of the engine bay.

The DPF regen triggers on fill (Well, strictly pressure, and a full filter results in higher DPF pressure). When all working as intended, I would expect 400-800 miles between regens, depending on driving and engine health and therefore soot production. The regen will only start if certain other parameters are met e.g. more than 25% fuel in tank, a minimum speed and min exhaust temp.

If you interrupt a regen (by switching the engine off mid way through, and you wouldn't normally know because there is no dash indicator), then it will probably try to do another regen ASAP once the car is on again and the parameters are met.

One of the suggestions made by the go to and also my thoughts was oil/diesel on the engine from previous leaks. This was a fair few miles since now and although I can’t guarantee it, I would think that the residue’s would have cleared up by now? Maybe not 🤔 this is something I can look at my self though.

I’m quite sure that the dpf location is not within the engine bay but somewhere under the drivers seat (externally of course) and is enclosed or half shrouded within its own heat shield. Not saying that lubes could travel down to that location mind.

I’ll have a good look to see if I can find anything obvious. But I reckon it’ll be another trip to the pros. I love the van, it’s comfortable, spacious and easy peasy with the kids. It’s just an annoyance that the issues could be a multitude of things.

Thanks for your feedback, I’ll hopefully be back one this thread with an update and solution that may help others out in the future.
 

BTB 500

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What mileage is it on?

We have a mechanically identical V6 Vito which has had a few issues over the years ... generally though any problem puts it into limp mode (with or without the EML coming on). One thing I found quite quickly was that our good/trusted local garage really struggled with it - they had it for 2 weeks but their diagnostic system wasn't able to properly clear some error codes relating to the EGR valve after fitting a new one. I took it to a dealer in the end and they sorted it in a day.

The gearbox thing is a bit worrying only 2k miles after the ATF was changed - did it drive OK before that? If so I'd get the fluid level checked to be on the safe side.
 

tjamesbo

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You cant beat someone who specialises in these engines and boxes ie a good merc independant (who will have star diagnostic eqt if reqd ) where are you there are many round the country recommended on here and many where members on here travel a couple of hundred miles to take their beloved .... CAR LOL you can check the basics but its hard to beat someone who does it on these engines and boxes day in and day out and they know the cheaper repairs
Boyd
 
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technodiv

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What mileage is it on?

We have a mechanically identical V6 Vito which has had a few issues over the years ... generally though any problem puts it into limp mode (with or without the EML coming on). One thing I found quite quickly was that our good/trusted local garage really struggled with it - they had it for 2 weeks but their diagnostic system wasn't able to properly clear some error codes relating to the EGR valve after fitting a new one. I took it to a dealer in the end and they sorted it in a day.

The gearbox thing is a bit worrying only 2k miles after the ATF was changed - did it drive OK before that? If so I'd get the fluid level checked to be on the safe side.

The mileage is around 132000. I had no previous problems with the gear change before that! Bit of a lazy question but where is the fill point for the ATF? As far as I’m aware the garage is packing the latest diagnostic stuff.

When I took it in before Christmas it was a bit of a rush job where they squeezed me in. I turned up out of the blue and explained the smell and they had it for about 5 hours before I needed it back to travel back up north to see the family over the holidays. They couldn’t find anything obvious but I’m guessing that it was a quick visual check. They did tell me to call back after, this is just the in between part to see if I can sort anything daft out!!
 

BTB 500

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OK, ours is on 135k miles now so pretty similar. Not sure where the ATF fill is ... you do need a separate dipstick to check the level (there isn't one with the vehicle). If it was driving fine before I would suspect low fluid or (worse, but hopefully less likely) the wrong spec. fluid used.

Our local garage had up to date diagnostic kit (and had previously worked on our Audi A4 with no issues), but the EGR problem I had on the Vito needed an MB STAR system. Only MB specialist garages or main dealers tend to have these.
 
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technodiv

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You cant beat someone who specialises in these engines and boxes ie a good merc independant (who will have star diagnostic eqt if reqd ) where are you there are many round the country recommended on here and many where members on here travel a couple of hundred miles to take their beloved .... CAR LOL you can check the basics but its hard to beat someone who does it on these engines and boxes day in and day out and they know the cheaper repairs
Boyd

I agree, At this stage of my rookie abilities, I wouldn’t touch engine or gearbox too much on the Merc (that’s what the old Landy is for!) I’m in Colchester and I’ve always took it to ‘Cowdray Car Centre’. They’re a fantastic team and I trust them. I’m confident that they’ll be able to solve the issue but I’d be happy to hear of any alternative garages just in case??

When I first bought the van and I was new to the area, I’d taken my previous pathetic excuse of a car to them (3 series) once before, I’d had the van checked over by RAC prior to the purchase but took it to Cowdray for a follow up check to be sure. I didn’t tell them about the RAC check and I also threw a few red herrings in, knocking/funny sounds etc. my reckoning for this was to see if they’d contradict anything RAC had reported. When I collected the van I was given a bill of around £80 and was told there were no probs 🤷‍♂️

I’m a family man and a tight northerner through and through and by trade! So trusting a garage to keep my vehicle/family and pocket safe is a big thing for me. I cannot recommend them enough 👍
 
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technodiv

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OK, ours is on 135k miles now so pretty similar. Not sure where the ATF fill is ... you do need a separate dipstick to check the level (there isn't one with the vehicle). If it was driving fine before I would suspect low fluid or (worse, but hopefully less likely) the wrong spec. fluid used.

Our local garage had up to date diagnostic kit (and had previously worked on our Audi A4 with no issues), but the EGR problem I had on the Vito needed an MB STAR system. Only MB specialist garages or main dealers tend to have these.

No dip stick! Sounds like a ‘find out’ mission to me (the wife won’t be happy with me) 🤭

I was thinking low/wrong fluid but I’m confident the correct type was put in ….. I was also thinking that if the exhaust is blowing, could pressure somehow affect gear change? Like I said, I’ll look for owt obvious but a trip to pros is on the cards …. Now where did I leave that rubber cheque book 😁
 

suty455

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The smell and the 2k gear change sounds like the DPF is doing a Regen it also gets louder, a common issue is a faulty DPF sensor which tells the system it needs a clean so you get a fast idle changes around 2k maybe more on a 5g box and it smells like hot oil.
Its also not uncommon to have change issues after a transmission service if they didnt swap the filter, the conductor plates can start to play up after a service as well, its best to factor the cost of this into the service and do it all at once.
 
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technodiv

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The smell and the 2k gear change sounds like the DPF is doing a Regen it also gets louder, a common issue is a faulty DPF sensor which tells the system it needs a clean so you get a fast idle changes around 2k maybe more on a 5g box and it smells like hot oil.
Its also not uncommon to have change issues after a transmission service if they didnt swap the filter, the conductor plates can start to play up after a service as well, its best to factor the cost of this into the service and do it all at once.

I reckon the dpf sensor could be faulty especially if it’s a common problem. The high revs are a regular occurrence so that may indicate that the sensor is stuck on ‘do a regen’? Would star diagnostics pick up on this being faulty or can this be done visually? When I do get the van in to the garage I’ll be asking about all the ifs buts and maybes that have been mentioned on here. Unexpected costs keep getting in the way!!
 
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technodiv

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Bit of an update, I don’t know how I missed it …. The exhaust was more than slightly blowing. It was pretty much detached from where the flexi meets the DPF! Since I repaired this section of the exhaust I have not experienced the fume issue. The increased gear change revs are still present but the fast idle does not seem to be. I’ll update this thread accordingly with the outcome and hopefully diagnosis of the still present issues for the benefit of other members experiencing the same things.

ECAF91F5-6AEE-416A-BFDC-A028CD527439.jpeg

7658C743-C436-48CB-9EEE-AF7FCDBE84F6.jpeg

93A200EC-BAB6-4654-959D-DDE4B7178382.jpeg

6EED2982-E9C2-48CF-8EBE-54359845CA71.jpeg

The third photo does not show the job finished. I’ve since finished it with the exhaust clamps in the correct place. I thought I’d add the photo of the rear of the DPF to maybe hear comments on its condition? It seems pretty clean and the holes do not look clogged, having said that, I would expect all the accumulation of soot/ash be at the front of the filter?

Thanks for all the advise u onto now 👍
 
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technodiv

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The smell and the 2k gear change sounds like the DPF is doing a Regen it also gets louder, a common issue is a faulty DPF sensor which tells the system it needs a clean so you get a fast idle changes around 2k maybe more on a 5g box and it smells like hot oil.
Its also not uncommon to have change issues after a transmission service if they didnt swap the filter, the conductor plates can start to play up after a service as well, its best to factor the cost of this into the service and do it all at once.

Also reading the invoice of works, the filter was replaced 👍
 

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